Magnetic braking system

ABSTRACT

A magnetic braking system for braking the motion of a moving member including first magnet means mounted on the moving member, a support frame positioned proximate the moving member, second magnet means having a polarity opposite the polarity of the first magnet means secured to the support frame, and positioning means for moving the second magnet means on the support frame to a position proximate the first magnet means wherein the magnetic flux between the first and second magnet means brakes the motion of the moving member.

United-State's Patent v [72] lnventor' Robert C.'Gray 2,768,316 10/1956Neiss 310/95 280 Clifford St., Blackfoot, Idaho 83221 1 pp No 846 471 1Pnmary Exammer-D. X. Slmey Filed July 31 1969 AttorneyC. Harvey Gold[451 Patented May 18, 1971 [54] MAGNETIC BRAKING SYSTEM ABSTRACT: Amagnetic braking system for braking the mo- 10 Claims, 9 Drawing Figs. vh

1 tron of a moving member including first magnet means [52] U.S. Cl310/93 nted n the moving member, a support frame positioned Cl 49/10proximate the moving member, second magnet means having Field of310/103, a polarity opposite the polarity of the first magnet means 105,10 secured to the support frame, and positioning means for moving thesecond magnet means on the support frame to a posi- [56] Rekmmes cuedtion proximate the first magnet means wherein the magnetic UNITED STATESPATENTS flux between the first and second magnet means brakes the1,333,415 3/1920 Henry 310/103 motion of the moving member.

l8 3B IO Patented May 18, 1971 2 Sheets-Sheet l r/az I N VENTOR. ROBERTC. GRAY CM HIS ATTORNEY Patented May 18, 1971 I 3,579,003

2 sheets-sneetz FIG. 5

INVENTOR.

I R0271 C.GRAY

HIS A-fToRNEY :1 MAGNETIC BRAKING SYSTEM BACKGROUND OF THE INVENTION.Mechanical braking systems which include a friction element that isapplied to an element in motion are well known. The friction andresulting drag between the coacting elements, of course, act as a brakeon the movement of the one element.

However, because of the friction required to effectuate brak- BRIEFDESCRIPTION OF THE INVENTION In its broadest form the inventioncomprises a magnetic braking system for braking the motion of a movingmember which comprises. first magnet means mounted on the moving member;a fixed support frame positioned proximate said moving member; secondmagnet means having a polarity opposite the polarity of said firstmagnet means secured to said support frame; and positioning means formoving said second magnet means on the support frame to a positionproximate said first magnet means wherein the magnetic flux between thefirst and second magnet means brake the motion of said moving member.

In another embodiment of the Y invention the moving member is a rotorand the first magnet means comprises a plurality of bar magnets radiallymounted on the rotor.

In still another embodiment of the invention the first magnet means is abar magnet and the second magnet means can be moved to a positionproximate each end of the bar magnet.

In yet another embodiment of I the invention the second magnet meanscomprises a plurality of bar magnets movably mounted on the supportframe to coact with a plurality of bar magnets attached to a rotor.

BRIEF DESCRIPTION OF THE DRAWINGS So that the invention may be morereadily understood and carried into effect reference is made to theaccompanying drawings which are offered by way of example only and arenot to be taken as limiting the invention, the scope of which is definedby the appended claims which are intended to embrace equivalentstructures.

FIG. 1 is an end view of one type of magnetic braking device conformingto the system of this invention. a

FIG. 2 is a sectional view taken in the line of 2-2 of FIG. I looking inthe direction of the arrows.

FIG. 3 is a side view of the braking device shown in FIG. 1.

FIG. 4 is a top view of a stator end plate.

FIG. 5 is a top view of one type of positioning rotor suitable for usewith the-braking device of this invention.

FIG. 6 is a top view of a spacer ring.

FIG. 7 is a front view of the bar magnet rotor and connected supportshaft.

FIG. 8 is a front view of apreferred magnet rotor.

FIG. 9 is a sectional view of FIG. 8 taken in the plane of line 9-9looking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more specificallyto the magnetic braking system of this invention. Rotor shaft 10 isrotatably mounted at one end to stator 12 to extend axially outward awayfrom one of the stators end plates 14. Rotor 16 is fixedly connected toshaft 10 so that rotation of the shaft is imparted to the rotor. Aplurality of magnets 18, hereinafter described, are affixed to rotor 16for braking purposes. Stays 20 and 22 are connected to shaft I0 onopposite sides of stator 12 to prevent the shaft from axially moving outof the stator as it rotates therein. Stator-'12 includes end plates 14positioned on opposite sides of a positioning rotor 24 with spacer'ring26. The stator is secured together with conventional clamping means suchas bolts 28" so that rotor 24. easily rotates between said end platesand thereby position internallylmounted bar magnets 30 towards thestators center axis and away from said axis as hereinafter described.

A plurality of radially extending guide slots 32, sized to slidablyreceive the end of a transversely positioned bar magnet 30, are formedin eachof the end plates 14. Accordingly, by properly spacing the endplates bar magnets 30 radially move in the stator towards and away fromits center axis while being held in a position substantially parallel tosaid center axis. Movement of the bar magnet 30 is controlled throughthe movement of handle 34 secured to positioning rotor 24 and passedthrough the opening in spacer ring 26. To ensure ease in operation,rotor-24 can ride on ball bearings 36 which in turn ride in a bearingrace formed along the inside face of spacer ring 26. Bar magnets 30extend through arched rotor slots 38 and areslidably mounted therein sothat magnets 30 are urged to move radially inward or outward in the endplate guide slots 32 when positioning rotor 24 is turned. Bar magnets 30are preferably of a circular or rod design to ensure ease of operation.In addition, all of the magnets 30 are preferably mounted between endplates 14 so that common poles are positioned on the same side of stator12, e.g., the north poles 40 of the magnets are positioned on the sideof the stator adjacent to rotor 16 and the south poles 42 of the magnetsare positioned on the opposite side of the stator.

Bar magnet rotor 16 is rotatably mounted to stator 12 so that magnets 18which are attached to the rotor are positioned adjacent to the end face44 of the stator. When magnets 18 are elongated bar-type magnets theyare preferably siaed to substantially correspond with guide slots 32formed in end plates 14 so that the ends of magnets 30 positionedadjacent to rotors 16 can move from one end to the other end of theradially extending bar magnets'by manipulating positioning rotor 24 asherein described. Optionally, as shown in FIGS. 8 and 9, bar magnets 18can be positioned endwise in rotor 16 at the proximate opposite ends ofguide slots 32.

Common poles of all of the bar magnets 18 secured to rotor 16 arepreferably positioned towards the center axis of rotor 16, e.g., thenorth poles 40 of magnets 18 are positioned inwardly towards the centeraxis of rotor 16 and the south poles 42 of the magnets are positionedoutwardly away from the center axis. Accordingly, depending on thearrangement of magnets 18 and 30 a magnetic attraction or repulsion isexerted therebetween. When there is a magnetic attraction a brakingforce is applied to rotation of rotor 16 with respect to stator 12because of the magnetic flux between the opposite magnet poles Tomaximize the braking effect the magnets are preferably arranged so thatthere is a magnetic attraction between them, i.e., dissimilar poles ofmagnets 18 and 30 are positioned adjacent to each other, when magnets 30are in their outermost position in guide slots 32 with respect to thecenter axis of stator 12. I

To operate the braking system of this invention rotor 16 is I rotatedwith respect to stator 12. Rotation continuesso long as the poles ofmagnets 18 are adjacent to similar poles of magnets 30, and this ispreferred. Braking of the movement of rotor 16 is effectuated by movingrotor handle 34 to thereby urge magnets 30 to a position in stator 12wherein their end poles are adjacent to dissimilar end poles of magnets18 and lines of braking magnetic flux are set up between said poles. Asindicated, the flux acts as a braking force to restrain continuedmovement of rotor 16.

It is to be noted that operation of the braking system of this inventionis maximized by constructing stator 12, and especially its end plate 14positioned adjacent to rotor 14, as well as said rotor 14, fromnonmagnetic materials such as brass, aluminum, stainless steel,synthetic resins such as nylon, etc. It is to be further noted thatwhile the invention specifically described herein relates to brakingmeans structure for a rotating member it is within the scope of thisinvention to apply the same magnetic braking principles hereindescribed,

other types of movement such as linear movement. It is also,

' of course, withinthe scope of this invention to use a stator withfixed magnets and provide means in combination with the rotor toreposition the magnets attached to the rotor.

lclaim;

l. A magnetic braking system for braking the motion of a moving membercomprising a support frame fixedly positioned with respect to saidmoving member; first magnet means attached to said moving member; secondmagnet means secured to said support frame having a polarity oppositethe polarity of the firstmagnet means; and positioning means connectedto said support frame and said second mag net means for moving thesecond magnet means to a position proximate the first magnet meansattached to said moving member wherein the magnet flux between the firstand second magnet means brakes the motion of said moving member withrespect to said support frame.

2. The magnetic braking system of claim 1 wherein said moving member isa rotor rotatably attached to said support frame. y

3. The magnetic braking system of claim 2 wherein said first magnetmeans comprises a plurality of radially extending bar magnets positionedabout the face of said rotor proximate said support frame such that themagnets have common poles positioned towards and away from the centeraxis of said rotor.

4. The magnetic braking system of claim 3 wherein said second magnetmeans comprises a plurality of magnets equal in number to the firstmagnets.

5. The magnetic braking system of claim 4 wherein the polarity of eachof the second magnets is opposite to the polarity of the ends of thefirst bar magnets positioned furthest away from the center axis of saidrotor.

6. A magnetic braking system for braking the motion of a moving membercomprising a support frame fixedly positioned with respect to saidmoving member; first magnet means attached to said moving member;"second magnet means secured to said supportframe'having a polarityopposite the polarity of the first magnet means; and positioning meansconnected to said moving member and said first magnet means for movingsaid first magnet means to a position proximate said second magnet meansattached to said support frame wherein the magnet flux'between the firstand second magnet means brakes the motion of said moving member withrespect to said support'frame 7. The magnetic braking means of claim 6wherein said moving member is a rotor rotatably attached to said supportframe.

8. The magnetic braking means of claim 7 wherein said second magnetmeans comprises a plurality of radially extending bar magnets securedto' the face of said support frame proximate said rotor such that themagnets have common poles positioned towards and away from the centeraxis of said rotor.

9. The magnetic braking means of claim 8 wherein said first magnet meanscomprises a plurality of magnets equal in number to the second magnets.

10. The magnetic braking system of claim 9 wherein the polarity of eachof the first magnets is opposite to the polarity of the ends of thesecond bar magnets positioned furthest away from the center axis of saidrotor.

1. A magnetic braking system for braking the motion of a moving membercomprising a support frame fixedly positioned with respect to saidmoving member; first magnet means attached to said moving member; secondmagnet means secured to said support frame having a polarity oppositethe polarity of the first magnet means; and positioning means connectedto said support frame and said second magnet means for moving the secondmagnet means to a position proximate the first magnet means attached tosaid moving member wherein the magnet flux between the first and secondmagnet means brakes the motion of said moving member with respect tosaid support frame.
 2. The magnetic braking system of claim 1 whereinsaid moving member is a rotor rotatably attached to said support frame.3. The magnetic braking system of claim 2 wherein said first magnetmeans comprises a plurality of radially extending bar magnets positionedabout the face of said rotor proximate said support frame such that themagnets have common poles positioned towards and away from the centeraxis of said rotor.
 4. The magnetic braking system of claim 3 whereinsaid second magnet means comprises a plurality of magnets equal innumber to the first magnets.
 5. The magnetic braking system of claim 4wherein the polarity of each of the second magnets is opposite to thepolarity of the ends of the first bar magnets positioned furthest awayfrom the center axis of said rotor.
 6. A magnetic braking system forbraking the motion of a moving member comprising a support frame fixedlypositioned with respect to said moving member; first magnet meansattached to said moving member; second magnet means secured to saidsupport frame having a polarity opposite the polarity of the firstmagnet means; and positioning means connected to said moving member andsaid first magnet means for moving said first magnet means to a positionproximate said second magnet means attached to said support framewherein the magnet flux between the first and second magnet means brakesthe motion of said moving member with respect to said support frame. 7.The magnetic braking means of claim 6 wherein said moving member is arotor rotatably attached to said support frame.
 8. The magnetic brakingmeans of claim 7 wherein said second magnet means comprises a pluralityof radially extending bar magnets secured to the face of said supportframe proximate said rotor such that the magnets have common polespositioned towards and away from the center axis of said rotor.
 9. Themagnetic braking means of claim 8 wherein said first magnet meanscomprises a plurality of magnets equal in number to the second magnets.10. The magnetic braking system of claim 9 wherein the polarity of eachof the first magnets is opposite to the polarity of the ends of tHesecond bar magnets positioned furthest away from the center axis of saidrotor.